Sylvania



r A .4 15,835 May 13 1924 c. A. Bonnie Re 'lanscrnrcAL lusqnpe u srnuunnv'r origina F119@ Sim. 21

1.1 bii yla 1J INVENToR lanemedoade ATTORNEY wrrNEssEs:

Reissued May 13, 1924.

UNITED STATES 4CLARENCE A. BODDIE, OF WILKINSBURG,

PENNSYLVANIA, ASSIGNOR ,T WESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA.

ELECTRICAL MEASURING INSTRUMENT.

0rlinl1 No. 1,298,616, dated March 1.1, 1919, Serial 110.151,890, filed September 21, 1915. Application for reissue led August 4, 1920. Serial No. 401,266. i

i `U and State of Pennsylvania, have invented a new and useful Improvement in Electrical Measuring Instruments, of which the following is a. specication.

My invention relates to electrical measl. uring instruments and particularly to voltam ere meters.

e object of my invention is to provide an instrument, of the above indicatedy character, that is simple in construction and efll fective in operation.

In the carrying out of my invention, I connect the potential Winding of an ordinary induction-type wattmeter to the circuit, the volt-amperes of which are to be 'il measured, and I interpose, between the current winding of the wattmeter and the circuit, means forjso controlling the current that traverses the current winding that it shall be proportional to the current traversthe circuit and shall have a predetermined phase relationship to the current traversing the potential winding, irrespective of the power factor ofthe circuit.

The device that is interposed between the 780 current winding and the circuit comprises a Kelvin balance the windings on one end of which are connected in series relation to the circuit and the windings on the other end of which are connected in `an auxiliary circuitY '85 comprising an adjustable resistor and the current winding. The auxiliary circuit, thus constituted, is connected in shunt relation to the main circuit. The balance is adapted. to so vary the resistance of the resistor that the l 4.0 current winding is supplied with currentl which is proportional `to the current traversing the circuit and hask a predetermined phase relationship to the current traversing the potential winding, irrespective of the rpower factor of the circuit.

The single re of the accompanying drawing is a digaugrammatic illustration of van electric circuit tok which is connected a volt-am re meter embodyng my invention.

l|50 An a ternating-current electric circuit 1 has a volt-ampere meter 2 connected thereto that comprises, in general, an electro-respon- `sive device 26, a Kelvin balance 11, a resistor I8 land a motor 2,1.

The electro-responsive device 26 comprises a magnetizable core member 3, a potential winding 4 that is operatively connected to the circuit 1, a current winding 5 and an armature 6 that is mounted on a shaft 7. The shaft 7 is biased toward a predetermined position by a spring 8 and has a pointer 9 mounted thereon that co-operates with a scale 10 to indicate the deflections of the armature 6. The Kelvin balance 11 is provided with a movable member 12 and two sets of windings 13 and 14, and is interposed between the current .winding 5 and the circuit 1 in a manner hereinafter more fully set forth.

The windings 13 of the Kelvin balance are connected to the secondary winding 15 of a series transformer 1'6 the primary winding.

17 of which is connected in series with one conductor of the circuit 1. The windings 14 are connected in a circuit comprising the current winding 5 of the electro-responsive device 26 and a resistor 18, and the circuit, thus constituted, is connected in shunt relation to the circuit 1. The resistor 18 is provided with a movable contact member 19 that is mounted on the shaft 20 of the motor 21. A movable contact member 22 is mounted on the movable member 12 of balance 11 and is adapted to engage either of two sta- Y tionary contact members 23 and 23a. The contact members 23 and 23a are connected to the respective terminals -of a resistor 27. The mid point of the resistor 27 is connected to one terminal of the field winding 24 of the motor 21, and the other/terminal of the field winding is connected to the contact member 22. A source of electromotive force 25 is connected between one terminal of the armature of the motor 21 and one terminal of the resistor 27, and the other terminal 'of the resistor 27 is connected to the remaining terminal of the armature. With such an arrangement of circuits, the armature of the y the movable contact member 22. The en gagement of the contact members causes the motor 21 to rotate and the resistor 18 lto be so adjusted that suiicient current is permitted to traverse the windings 14 and 5 to return the balance to its mid position. The current that traverses the winding is thus proportional to the current traversing the circuit 1, but, since the circuit comprising the windings 5 and 14 and the resistor 18 is connected in shunt relation to the circuit 1, the current traversing the same will have a predetermined definite phase relationship with respect to the current traversing the winding 4. Thus, irrespective of the power factor of the circuit 1, the phase relation between the currents traversing the windings 4 and 5 is substantially deiinite and constant. The torque produced by the armature 6 is proportional to the product of the current in the windin s 4 and 5 and, therefore, to the product o current and potential of the circuit 1.l

It is a well known fact that, in order to produce a torque on the armature 6, the currents traversing the windings 4 and- 5 must be out of phase with respect to each other. Consequently, the circuit, comprising the windings 5 and 14 and the resistor 18, is so proportioned that the current traversing the same bears a definite out-ofphase relation to that which traverses the winding 4. Since this phase relation is substantially constant for rall power factors of the circuit 1, because the windings 4 and 5 are both connected in shunt relation to the circuit, it will be readily understood that the torque exerted on the armature 6 will be proportional to the product of two currents one of which is proportional to the potential and the other of which is proportional to thecurrent 'traversing the circuit 1.

I do not limit my invention to any particular types of instruments, as many modifications may be made in the same without departing from the spirit and scope of my invention as set forth in the appended claims. f

I claim as my invention:

1. A -volt-ampere meter for an alternating-current circuit comprising a plurality of co-operatin means energized by only one` quantity o the circuit and in fixed-phase relation and means for so affecting said means as to actuate the meter in accordance with the volt-amperes of the circuit.

2. A volt-ampere meter for an alternating-current circuit com rising a movable member, actuating windings therefor energized by only one quantity of the circuit and 1-n fixed-phase relation and means responsive to variations in another' quantity of the cirduit for causingl the Vwindings to actuate the movable member in accordance with the volt ampres of the circuit.

3. A volt-ampere meter for an alternating-current circuit comprising a movable member, actuating windings therefor energized b only one quantity of the circuit and in Xed phase relation and one of which is energized in accordance with one of the factors of the apparent power of thev circuit, and means for varying the magnitude of the current in another winding in accordance with the other factor of the apparent power of the circuit.

4. A volt-ampere meter for an electric circuit comprising a potential and a current winding and means interposed between the circuit and the current winding whereby the current winding is supplied with current proportional to .the current that traverses the circuit and bearing a predetermined definite phase relation to the current traversing the potential winding, irrespective of thel power factor of the circuit.

5. A volt-ampere meter for an electric circuit comprising co-operating potential and current windings, a Kelvin balance operatively connected to thecircuit and to the current winding and means controlled by the Kelvin `balance for controlling the current that traverses the `current winding.

6. `A volt-ampere meter for an electrlc circuit comprising a potential and a current `is proportional to the current traversing the circuit.

l7. A measuring instrument for an altermating-current circuit comprising `a movable member, co-operating vwindings connected across the circuit for exerting a `torque on the movable member and means connected to the circuit for so controlling the current traversing one ofthe windings that the torque exerted on the movable member will vary in accordance with the product of the current and voltage of the circuit. Y

8. A volt-ampere meter for an alternating-current circuit comprising a movable member, actuating windings therefor energized b only one quantity of the circuit and 1n fixe -phase relation, one of said windings being energized in accordance with one of the factors ,of the apparent power of the circuit, and means for varying the resistance loo member, windings connected in shunt relation to the circuit and means for so controlling the current traversing one of the windings that the movable member develops a to ue directly proportional to the product dil the current and voltage of the circuit.

10. A measurin tric circuit comprising a winding, a Kelvin balance o eratively connected to the circuit and a resistor controlled by the balance for controlling the current supplied to the winding from the circuit.

1-1. A measurin instrument for an electric circuit comprising a winding, a Kelvin' yalue of the current traversing the wind- 13. A volt-ampere meter for an alternating-current circuit comprising an instrument having coils one of which is directly energized from the circuit and means for su ying another coil with current from sai in accordance with the apparent power ltraversing the circuit, and comprising a direct electrical connection between said last named coil and said circuit.

14. A volt-ampere meter for an alternating-current circuit comprising a movable member, iux-producing means therefor, means responsive to one of the uantities of the circuit and a ilux-contro ing device electrically associated with said quantityresponsive means and connected to the circuit and co-operating with said flux-producing means.

15. A volt-ampere meter for an alternating-current circuit comprising a movable instrument for an elec-- circuit so that the meter is actuated member, voltage and current windings therefor arranged for connection to the circuit, means responsive to one of the quantities of the circuit, and a circuit-controlling device connected in series with a portion of said quantity-responsive means and between one of the meter windings and the circuit.

16. A volt-ampere meter for an alternating-current circuit comprising a movable member, voltage and current windings therefor arranged for connection to the circuit, means responsive to one of the quantities of the circuit, and a circuit-controlling device electrically connected to one ofy the windings of the meter, to a portion of the quantity-responsive meansl and to the circuit.

17. A volt-ampere meter for an alternating-current circuit comprising co-operating elements one of which is energized in proportion to one of the components of the apparent power of the circuit, means including`- a movable member between another of said elements and the circuit, and means including a movable member aiected by only one quantity of the circuit and co-operating with said first means to energize said other element in accordance with the other component of the apparenty power of the circuit.

- 18. A volt-ampere meter for an alternating-current circuit comprising co-operating windings, one of which is energized in proportion to one of the components of the apparent power of theL circuit, means including another of said windings energized from the circuit, and means responsive to only one quantity of the circuity and co-o erating with said first means to cause said other winding to be energized in proportion to the other component of the apparent power of the circuit.

In testimony whereof, I have hereunto subscribed my name this 21st day of July,

CLARENCE A. BODDIE. 

